Lifting-jack.



M. L. JENKINS.

LIPTING JACK APPLICATION mum DEO.14, 1906 902,884. Patefited Nov. 3, 1908.

is W dam-662W WfM ating crank the end of the handle being UNITED sTirTEs" i i-rrniv'r OFFICE.

MERRILL L. JENKINS, OI HARVEY, ILLINOIS, ASSIGNOR TO BUDA FOUNDRY (K: MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

LIFTING-JACK.

To all whom it may concern:

Be it known that l, MERRILL ll. JENKINS, a citizen of the United States, residing at llarvey, in the county of (look and the {State of Illinois, have invented certain new and useful Improvements in Lifting-Jacks, of which the following is the specification. 1

My invention relates to lifting jacks, and has for its objects; to provide an improved and less expensive form of reduction gearing than has heretofore been employed; to provide a construction in which there is no necessity for changing the ratchet and pawl operating means for varying loads, and to provide an arrangement in which a change in the speed of operation may be accomplished from a single operating shaft. These and other objects which will be apparent to those skilled in the art are accomplished by my invention, one embodiment of which is illustrated in the accompanying drawing in which- Figure 1 is a transverse section through the jack, the operating crank being shown in dotted lines,

Figure 2 is an enlarged detail of the operbroken away, and

Figure 3 is an enlarged detail of the operating lever which may be substituted for the crank.

One of the objects of my invention as above stated is to reduce the cost of the reduction gearing and this I accomplish by making the main gear on the screw lifting bar a spur gear instead of the bevel gear as has heretofore been done. Certain of the other gears employed must necessarily be bevel gears but these gears are much smaller and can be cut at small expense, so that the cost of the gearing is much reduced by this arrangement. This arrangement is not only less in cost but provides a superior arrangement mechanically as the bearing for the countershaft carrying the small side gears can be more rigidly supported than was heretofore possible in the old arrangement of gearing. The second object accomplished by the invention is the doing awa with the two operating shafts for use wit different loads, which shafts were placed at different points in the train of reduction gearing and differed in the amount of power required for operation and consequently in Specification of Letters Patent.

Application filed. December 14, 1906.

the speed of operation. This arrangement Patented Nov. 3, 1908.

Serial No. 347,764.

for changing the operating means has been found objectionable because of the amount of time lost due to the removing the cotter pin which held the pawl and ratchet n1echanism in place on the operating shaft and to the fact that the ratchet wheel was forced out of position when the lever was taken from the operating shaft. \Vhen placed on the other shaft such wheel had to be repositioned. To avoid this difiiculty I use a high reduction gearing with a single operatmg shaft, and in order to secure a different speed of operation I use interchangeable operating handles of such shape that one may be operated at much higher speed and. with less power than the other, thus accomplising the same result that was accomplished in the old arrangement by using the two operating shafts.

Referring now to Figure 1 of the drawing, 1 is the standard of the jack with the base 2, 3 is the lifting bar provided with the screw 4 which engages with a suitable collar, 5 on the standard 1 in the usual way, 6 is the cap mounted on the lifting bar, 7 is a guide member mounted on the cap and provided with the usual lifting step 8, 9 is the antifriction bearing on which the cap 6 turns and 10 is the lug on the guide part 7 for carrying the reduction gearing.

As heretofore indicated the gearing employed is one of the features of my invention and its construction will now be described. Keyed to the screw lifting bar 4 is the spur gear 11 which spur gear engages at one side the pinion 12, whic 1 pinion 12 is mount-ed on the countershaft 13 carried by the projecting part 10. The countershaft 13 also carries the bevel gear 14 which in turn meshes with the bevel gear 15 carried by the operating shaft 16. The shaft 16 is mounted on the removable plate 17 in the usual way and is provided at its end with a squared portion for engaging the ratchet wheel 18 and the end of the member 19 which carries the pawl 20 in the usual way. The member 19 is provided with a socket 21 adapted to re ceive the end of the crank 22 as indicated in dotted lines in Figure 1. A set screw 21 holds the end of the crank in position. If light loads are to be raised and the shaft 16 rotated rapidly the crank members 22 can be used, but when heavier loads are to be raised the lever 23 is used in place of the crank 22, the ends of the crank and the lever being similar and adapted to detachably engage the socket 21. The reduction gearing including the gears 12, M and 15 it will be seen is a high one, so that with the lever 23 upon the shaft a very slow movement of the load is secured, while with the crank 22 substituted for the lever 23 a more rapid movement may be accomplished on account of the continuous crank motion, and because of the short lever arm.

From the foregoing it will be apparent that the applicants gearing is a comparatively inexpensive one as the gear 11 can be cheaply cut as can also the spur gear 12 and the bevel gears 14 and 15 are so small that the expense of their production is a small matter. It will also be seen that the countershaft 14 is firmly supported at either end by the projecting lug portion 10, and the lifting bar 8, the countershaft 13, and the operating shaft 16 are all rigidly secured with respect to each other. It will also be apparent that by the use of the socket 21, the crank 22 and the lever 23 changes in speed of operation may be seeured without any loss of time, as it is a sim le matter to disengage the members 22 an 23 from the socket, which operation requires only a fraction of the time consumed in the changing of the cotter pin, the ratchet and pawl from one operating shaft to another as was done in the old form of device.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent, is the following:

In combination in a jack, a standard, a screw lifting bar, a guide member carried by the lifting bar, a spur gear on the lifting bar, a vertical countershaft carried by the guide lneniber, a pinion meshing with the spur gear and a bevel gear both mounted on the coun tershaft, an operating shaft at right angles to the countershaft and a bevel gear thereon meshing with the bevel gearing on the coun tershaft.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses.

MERRILL L. JENKINS.

\Vitnesses E. M. ADAMs, J NO. L. WALKER. 

